Chemical immobilisation of free-ranging Pampas foxes (Pseudalopex gymnocercus): Assessment of ketamine-xylazine and tiletamine-zolazepam combinations

Two protocols to immobilise free-ranging Pampas foxes for ear-tagging or radio-collaring were evaluated. One hundred fifteen foxes were injected with ketamine-xylazine (K-X) and thirteen with tiletamine-zolazepam (T-Z). The use of both T-Z and K-X combinations typically resulted in a smooth induction and recovery. In 86% of the cases K-X protocol was judged effective (mean ± SD, K: 10.7 ± 3.3 mg/kg, X: 1.0 ± 1.0 mg/kg) while T-Z protocol was judged effective in 92% of the cases (T: 3.6 ± 1.05 mg/kg, Z: 3.6 ± 1.05 mg/kg). The primary differences between the two drug combinations were that the time necessary for the complete recovery was longer with T-Z, and thermic problems were found more frequently with K-X. Additionally, our results suggest that thermic stress may be a relatively frequent complication for Pampas foxes. This study provides baseline data on some physiologic variables in Pampas foxes captured with different methods and drugs in field conditions.